"Universal design for learning (UDL) is a framework to improve and optimize teaching and learning for all people based on scientific insights into how humans learn." (CAST, 2018))
UDL offers principles and guidelines for curriculum design, teaching methods, materials, and assessments that work for all students rather that a single, one-size-fits-all method; instead UDL uses accommodating practices that are flexible and can be adapted for individual learning requirements.
Similar frameworks to UDL are Universal Instruction Design (UID) and Universal Design for Instruction (UDI). All are based around the concept of inclusive education using universal design.